For me, it's social dancing, specifically West Coast Swing. Because while there is just social dancing, and some who only do it, there's a bit of a culture of competition, and it has its own governing body for determining where you place in competitions, and when it does sound like a cult when described.
Tabletop miniature games. >!Except we probably are a cult send help they wont let me do anything except basecoat.!<
This gets double bad if there's two of you (tabletop games) and one of them.